Method for treating tissue

ABSTRACT

A method for treating tissue is provided. The method comprises introducing into a patient the distal end of a catheter. The catheter comprises a catheter shaft comprising an elongated tubing having proximal and distal ends, and a distal shaft comprising a tubing having proximal and distal ends. The distal shaft carries a treatment device along a side of the distal shaft. A hinge is mounted between the distal end of the catheter shaft and the proximal end of the distal shaft. The hinge enhances the ability of the distal shaft to bend relative to the catheter shaft in a single predetermined plane A force is exerted on the distal shaft to cause at least a portion of the treatment device that is along a side of the distal shaft to contact the tissue. The tissue is treated with the treatment device.

FIELD OF THE INVENTION

[0001] The present invention relates to an improved method for treatingtissue using a device having a hinge to enhance the ability of thedevice to bend in a desired direction.

BACKGROUND OF THE INVENTION

[0002] Deflectable catheters are widely used for a variety ofapplications. In the area of electrophysiology, it is often desirable tointroduce a portion of a catheter carrying one or more electrodes into acertain region of the heart in order to map or ablate that region.However, due to their inherent flexibility, catheters can be difficultto control as precisely as would be desired. Accordingly, a needs existsfor a deflectable device, such as a catheter, having a mechanism toenhance the user's ability to control the degree and direction ofdeflection of the catheter.

SUMMARY OF THE INVENTION

[0003] The present invention provides a method for treating tissue witha deflectable device, such as a catheter, that includes a hinge thatenhances the ability of the device to deflect or bend within apredetermined plane. In one embodiment, the invention is directed to amethod for treating tissue comprising introducing into a patient thedistal end of a catheter. The catheter comprises a catheter shaftcomprising an elongated tubing having proximal and distal ends and adistal shaft comprising a tubing having proximal and distal ends. Thedistal shaft carries a treatment device having a surface along a side ofthe distal shaft. A hinge is mounted between the distal end of thecatheter shaft and the proximal end of the distal shaft. The hingeenhances the ability of the distal shaft to bend relative to thecatheter shaft in a single predetermined plane. A force is exerted onthe distal shaft, either directly, such as with a puller wire, orindirectly through the catheter shaft, to cause at least a portion ofthe surface of the treatment device that is along a side of the distalshaft to contact the tissue. The tissue is treated with the treatmentdevice.

[0004] In the case where the distal shaft comprises a flexible orinflexible tubing having a circular cross-sectional area, the side ofthe distal shaft refers to the outer circumferential wall of the distalshaft. In the case where the distal shaft carries a non-tubulartreatment device, such as a basket, such as that described in U.S. Pat.No. 6,292,695, the disclosure of which is incorporated herein byreference, or a balloon, such as that described in U.S. patentapplication Ser. No. 10/201,052 entitled “Ablation Catheter HavingStabilizing Array,” the disclosure of which is incorporated herein byreference, the side of the distal shaft includes the outer surface ofthe portion of the non-tubular treatment device that lies in a planethat is not perpendicular to the axis of the distal shaft, andpreferably that is generally parallel to the axis of the shaft. In otherwords, the side of the distal shaft refers to a portion of the distalshaft or surface of a treatment device other than a surface that isgenerally perpendicular to the axis of the distal shaft. For example, ifthe treatment device is a standard tip electrode mounted at the end ofthe distal shaft that has a generally flat distal surface (that lies ina plane perpendicular to the distal shaft) and an exposedcircumferential sidewall, the exposed circumferential sidewall of thetip electrode is a surface of a treatment device along the side of thedistal shaft. If the treatment device is an optic fiber, it wouldconstitute a surface of a treatment device along a side of the distalshaft if it extends out through a portion of the distal shaft in adirection that is not parallel to the axis of the distal shaft; if theoptic fiber extended parallel to the axis of the distal shaft, thetreatment surface, i.e., the tip of the optic fiber, is typicallyperpendicular to the axis of the distal shaft. As would be apparent toone skilled in the art, other treatment devices can be carried by thedistal shaft.

[0005] The hinge enhances the ability of the distal shaft to bendrelative to the catheter shaft in a single predetermined plane so thatit is easier for the distal shaft to bend relative to the catheter shaftin the predetermined plane than it is for the distal shaft to bend inother planes through which the distal shaft and catheter shaft extend.

[0006] This design is particularly advantageous when the treatmentdevice is along a side of the distal shaft, as described above.Specifically, if the surface of the treatment device is perpendicular tothe axis distal shaft, the user can simply exert a direct force alongthe axis of the distal shaft, the force thus being perpendicular to theaxis of the distal shaft. However, when the surface of the treatmentdevice is along a side of the distal shaft, it is more difficult toexert a force in the desired direction. However, when the hinge enhancesthe ability of the distal shaft to bend in a single plane, a greaterforce can be exerted on a surface of the treatment device positionedappropriately on a side of the distal shaft. The surface of thetreatment device is preferably positioned on a side of the distal shaftthat lies in the predetermined plane in which bending of the distalshaft is enhanced by the hinge.

DESCRIPTION OF THE DRAWINGS

[0007] These and other features and advantages of the present inventionwill be better understood by reference to the following detaileddescription when considered in conjunction with the accompanyingdrawings wherein:

[0008]FIG. 1 is a side view of an embodiment of the catheter of theinvention.

[0009]FIG. 2 is a side cross-sectional view of a catheter body accordingto the invention, including the junction between the proximal and distalregions of the catheter shaft of the catheter shown in FIG. 1.

[0010]FIG. 3 is a side view of the intermediate and distal shafts of thecatheter shown in FIG. 1.

[0011]FIG. 4 is an end cross-sectional view of the intermediate shaftshown in FIG. 3.

[0012]FIG. 5 is a perspective view of a hinge according to the inventionin a neutral configuration.

[0013]FIG. 6 is a perspective cutaway view of the hinge depicted in FIG.5.

[0014]FIG. 7 is a top view of the hinge depicted in FIG. 5.

[0015]FIG. 8 is a side view of the hinge depicted in FIG. 5.

[0016]FIG. 9 is a side view of the hinge depicted in FIGS. 5 to 8 in adeflected configuration.

[0017]FIG. 10 is an end cross-sectional view of the distal shaft shownin FIG. 3.

[0018]FIG. 11 is a cross sectional view of a portion of the catheter tipsection showing one means for attaching the puller wire.

[0019]FIG. 12 is a top cross sectional views of a preferred puller wireanchor.

[0020]FIG. 13 is a side cross sectional views of the puller wire anchorof FIG. 12.

DETAILED DESCRIPTION

[0021] The invention is directed to a deflectable device, such as acatheter, including a hinge that enhances the ability of the device todeflect or bend within a predetermined plane. In accordance with theinvention, the device can be deflected or bent upon application of apulling force from within the device, such as by the use of a pullerwire as is generally known in the art, or the device can be bent uponapplication of an outside force on a part of the device, such as bypushing a part of the device against tissue to cause the tissue tothereby exert a force onto a part of the device and bend that part ofthe device relative to the rest of the device. As used herein, the term“deflectable” describes catheters having a straight configuration in theneutral position that can be deflected into a curved configuration, aswell as catheters having a curved configuration in the neutral positionthat can be deflected into a straight configuration or into a differentcurved configuration.

[0022] In an exemplary embodiment of the invention, there is provided asteerable catheter having an irrigated electrode at its distal end. Asshown in FIG. 1, the catheter comprises an elongated catheter shaft 12having proximal and distal ends, an intermediate shaft 14 at the distalend of the catheter shaft over which the hinge is mounted, a distalshaft 16 at the distal end of the intermediate shaft on which one ormore electrodes or other devices are mounted for performing mapping,ablation or another desired function, and a control handle 18 at theproximal end of the catheter shaft.

[0023] In the depicted embodiment, the catheter shaft 12 has a proximalregion 20 and a distal region 22 having different degrees offlexibility. Such a design is particularly useful where it is desired todeflect the distal region 22 of the catheter shaft. Typically theproximal region 20 is substantially longer than the distal region 22,with the proximal region having an exemplary length ranging from about90 cm to about 120 cm, and the distal region having an exemplary lengthranging from about 1 cm to about 8 cm.

[0024] With reference to FIG. 2, the proximal region 20 of the cathetershaft 12 comprises an elongated tubular construction having a single,axial or central lumen 24. The proximal region 20 is flexible, i.e.,bendable, but substantially non-compressible along its length. Theproximal region 20 can be of any suitable construction and made of anysuitable material. A presently preferred construction comprises an outerwall 26 made of polyurethane or PEBAX. The outer wall 26 comprises animbedded braided mesh of stainless steel or the like to increasetorsional stiffness of the proximal region 20 so that, when the controlhandle 18 is rotated, the distal region 22 of the catheter shaft 12 willrotate in a corresponding manner.

[0025] Additionally, in the depicted embodiment, the inner surface ofthe outer wall 26 of the proximal region 20 is lined with a stiffeningtube 28, which can be made of any suitable material, preferablypolyimide. The stiffening tube 28, along with the braided outer wall 26,provides improved torsional stability while at the same time minimizingthe wall thickness of the catheter, thus maximizing the diameter of thecentral lumen 24. The outer diameter of the stiffening tube 28 is aboutthe same as or slightly smaller than the inner diameter of the outerwall 26.

[0026] The outer diameter of the catheter shaft 12 is not critical, butis preferably no more than about 8 french, more preferably 7 french.Likewise the thickness of the outer wall 26 is not critical, but is thinenough so that the central lumen 24 can accommodate an infusion tube, apuller wire, lead wires, and any other wires, cables or tubes.

[0027] The distal region 22 of the catheter shaft 12 comprises a shortsection of tubing having three lumens. The first lumen 30 a electrodecarries lead wires, the second lumen 32 a carries a puller wire, and thethird lumen 34 a carries an infusion tube, as described in more detailbelow. The tubing of the distal region 22 is made of a suitablenon-toxic material that is preferably more flexible than the proximalregion 20. A presently preferred material for the distal region 22 isbraided polyurethane, i.e., polyurethane with an embedded mesh ofbraided stainless steel or the like. The number and sizes of the lumensare not critical and will depend on the components to be carried by thelumens.

[0028] As noted above, the proximal region 20 and distal region 22 havedifferent degrees of flexibility to enhance deflection of the distalregion of the catheter shaft. However, if deflection of the distalregion is less important, the catheter shaft can have a single stiffnessalong its length. With such a design, the proximal and distal regionscan be made, for example, of a single piece of tubing having only asingle lumen extending therethrough. Other catheter shaft arrangementswill be apparent to one skilled in the art and are within the scope ofthe invention.

[0029] At the distal end of the distal region 22 of the catheter shaft12 is the intermediate shaft 14, which carries the hinge, and the distalshaft 16, which carries one or more electrodes or other diagnostic ortreatment devices. Specifically, as best shown in FIG. 3, theintermediate shaft 14 comprises a flexible plastic tubing, preferablyPEBAX. The distal shaft 16 similarly comprises a flexible plastictubing, preferably PEBAX. The intermediate shaft 14 is more flexiblethan either of the distal region 22 of the catheter shaft 12 or thedistal shaft 16 so as to not limit the ability of the intermediate shaftto bend, thereby allowing the hinge to control the extent and directionof bending of the intermediate shaft, as discussed further below. Unlikethe tubing that forms the catheter shaft 12, the plastic tubing thatforms the intermediate shaft 14 preferably does not include a braidedcore within the plastic. In one exemplary embodiment, the proximalregion 20 comprises 72D durometer plastic, the distal region 22comprises 55D durometer plastic, the intermediate shaft 14 comprises 35Ddurometer plastic, and the distal shaft 16 comprises 72D durometerplastic. The intermediate shaft 14 is connected to the distal end of thedistal region 22 of the catheter shaft 12 and to the proximal end of thedistal shaft 16 by any suitable method, for example, using thermal buttjoints.

[0030] In the depicted embodiment, the intermediate shaft 14 includesfirst, second and third lumens 30 b, 32 b, and 34 b that are alignedwith the first, second and third lumens 30 a, 32 a, and 34 a,respectively, in the distal region 22 of the catheter shaft 12.Similarly, the distal shaft 16 includes first, second and third lumens30 c, 32 c, and 34 c that are aligned with the first, second and thirdlumens 30 b, 32 b, and 34 b, respectively, of the intermediate shaft 14.As would be recognized by one skilled in the art, the number andarrangement of lumens in the intermediate shaft 14 can vary, but thelumens in the intermediate shaft are preferably aligned with the lumensin the distal region 22 of the catheter shaft 12 and in the distal shaft16, as discussed further below.

[0031] A hinge 40 is mounted over the intermediate shaft 14 to controlthe direction and extent of bending of the intermediate shaft. The hinge40 comprises a flexible tube, which can be made of any suitablematerial, such as Nitinol or plastic, having an outer wall 42 and aninner diameter that is slightly larger than the outer diameter of theintermediate shaft 14 so that the hinge can be mounted on the outside ofthe intermediate shaft, as shown in FIGS. 3 and 4. In the depictedembodiment, the hinge 40 covers the entire intermediate shaft 14 toreduce the tendency of the intermediate shaft to kink when the hinge isbent. The hinge 40 includes one or more slots 44 extending through theouter wall 42 of the flexible tube, which affect the direction in whichand extent to which the hinge can bend.

[0032] In the depicted embodiment, the slots 44 of the hinge 40 arearranged to permit the hinge to bend in a single plane in a singledirection and no more than approximately 90°. With reference to FIGS. 5and 6, the outer wall 42 of the hinge 40 has a compressible side 46 andan expandable side 48. The compressible side 46 is the side facing thedirection toward which the hinge 40 bends, where the bending results inthe compressible side of the hinge being compressed on itself. Theexpandable side 48 is the side opposite the compressible side 46.

[0033] The depicted hinge 40 includes a total of fourteen slots 44divided evenly between the compressible side 46 and the expandable side48. When the hinge is in the neutral position, which in the depictedembodiment is straight, as shown in FIGS. 5 to 8, each slot 44 isgenerally perpendicular to the axis of the hinge 40, although the slotscould alternatively be angled relative to the axis of the hinge so longas they are generally transverse to the axis of the hinge. The slots 44on the compressible side 46 (“the compressible slots 44 a”) are alignedwith the slots 44 on the expandable side 48 (“the expandable slots 44b”), i.e., arranged so that corresponding slots on the compressible sideand on the expandable side are positioned the same distance from an endof the hinge. As will become apparent, the number, placement, size andshape of the slots 44 can vary depending on the desired effect to beachieved. Preferably the total number of slots on the hinge ranges fromone to about thirty, more preferably from about ten to about twenty. Theslots 44 can be provided only on the compressible side 46, only on theexpandable side 48 or divided in any desired manner between the twosides.

[0034] In the depicted embodiment, the slots 44 are all the same depthQ, i.e., they all extend the same distance through the outer wall 42 ofthe hinge 40 towards the axis of the hinge. The depicted slots do notextend through the axis or center of the hinge 40, so that the depth ofeach slot is less than the outer radius of the hinge. If desired, theslots can be deeper than the outer radius of the hinge so that theyextend through the axis of the hinge 40, although with such a design itis preferred that the compressible slots 44 a not be aligned with theexpandable slots 44 b, but instead alternate in position. If desired,the compressible slots 44 a can have depths different from those of theexpandable slots 44 b. In another alternative, the compressible slots 44a of a single hinge can have varying depths and/or the expandable slots44 b can have varying depths.

[0035] The shapes of the slots 44 can affect the extent to which thehinge 40 will bend. In the depicted embodiment, the compressible slots44 a are generally keyhole-shaped when viewed from the side, as bestshown in FIG. 8. Specifically, each compressible slot 44 a comprises anelongated opening 50 having two ends of decreasing width and thatterminate in circular openings 52, which are preferably larger indiameter than the widest portion of the elongated opening. Thus, thecompressible slots 44 a involve the removal of material from theflexible tube that forms the hinge. In one embodiment, each elongatedopening 50 decreases in width at an angle of 13°, varying from a maximumwidth of 0.011 inch to an end width (near the circular openings 52) of0.006 inch, with the circular opening having a diameter of 0.020 inch,and with the distance D1 between the compressible slots 44 a beingapproximately 0.021 inch.

[0036] Each expandable slot 44 b comprises an elongated slot 54 ofinsignificant thickness, i.e., where no material is removed from theflexible tube, that terminates in a circular opening 56 like thecircular openings 52 of the compressible slots 44 a. In one embodiment,the circular openings 56 of the expandable slots 44 b have the same sizeas the circular openings 52 of the compressible slots 44 a, with thedistance D2 between the expandable slots 44 b being approximately 0.032inch, so that the expandable slots 44 b are aligned with thecompressible slots 44 a.

[0037] In use, when a force is exerted on the distal shaft 16, which ismounted on the distal end of the hinge 40, the hinge is bent in adirection toward the compressible side 46, as shown in FIG. 9. Thearrangement of the slots 44 forces the hinge to bend within the desiredplane. As the hinge 40 bends, the compressible slots 44 a are compressedso that the inwardly-angled openings 50 close, and the expandable slots44 b expand so that the elongated slots 54 of insignificant thicknessopen, as best depicted in FIG. 9. The inwardly-angled openings 50 aresized as described above such that they close and make further bendingvery difficult once the hinge 40 reaches a 90° angle. Because theexpandable slots 44 b comprise elongated slots 54 of insignificantthickness when the hinge is in the neutral position, it is difficult forthe hinge to bend in a direction toward the expandable side 48.Accordingly, the depicted hinge 40 is designed to bend in a single planein a single direction and no more than approximately 90°.

[0038] The integrity of the hinge 40 is maintained by including aflexible hinge cover 60 over the hinge. The hinge cover 60 is preferablymade of a biocompatable plastic, such as polyurethane, with aflexibility approximately equal to that of the intermediate shaft 14.The hinge cover 60, like the intermediate shaft 14, should not limit theability of the hinge 40 to bend. The hinge cover 60 protects the hinge40 against electrical conductivity, particularly when the hinge is madeof Nitinol or another metal, and also protects against blood and otherbodily fluids from entering and clogging the slots 44 of the hinge. Thehinge cover 60 is longer than the hinge 40 and has proximal and distalends extending beyond the hinge's proximal and distal ends,respectively. The hinge cover 60 can be secured in place over the hinge40 by any suitable method, such as by gluing or thermally bonding theproximal end of the hinge cover 60 to the distal region 22 of thecatheter shaft 12 and by gluing or thermally bonding the distal end ofthe hinge cover to the distal shaft 16.

[0039] Although the hinge 40 is described as being mounted over theintermediate shaft 14, it could also be mounted within the intermediateshaft, for example, if the intermediate shaft has a single centrallumen. Other arrangements for the hinge are also within the scope of theinvention. For example, the hinge can be formed by providing slotsdirectly into a portion of the tubing that forms the catheter shaft.

[0040] As noted above, the distal shaft 16 carries one or moreelectrodes for mapping and/or treatment or other treatment or diagnosisdevices. In the depicted embodiment, the distal shaft 16 carries aporous electrode arrangement comprising a coil electrode 62 wrappedaround a portion of the distal shaft over which is mounted a plasticsleeve 64.

[0041] The coil electrode 62 can be made of any electrically-conductivematerial, such as platinum or gold. The length of the coil electrode 62can vary depending on the desired application, and preferably rangesfrom about 5 mm to about 20 mm, more preferably about 11 mm.

[0042] The porous sleeve 64 can be made of any suitable biocompatableporous material through which fluid can pass, such as porouspolytetrafluoroethylene. Preferably the porous sleeve 64 is sufficientlyporous to permit saline to pass therethrough at a flowrate of at least 1cc/min, more preferably from about 10 cc/min to about 60 cc/min, stillmore preferably from about 20 cc/min to about 40 cc/min.

[0043] One or more irrigation openings 66 are provided in the wall ofthe distal shaft 16 that fluidly connect the third lumen 34 c of thedistal shaft to the outside of the distal shaft. In the depictedembodiment, the distal shaft 16 includes three irrigation openings 66,although this number can vary as desired. The irrigation openings 66 areprovided between the coils of the coiled electrode 62 and underneath theporous sleeve 64. The irrigation openings 66 permit fluid to pass fromthe third lumen 34 c of the distal shaft to the outside of the distalshaft within the porous sleeve 64 and then through the porous sleeve.The fluid is preferably saline or other conductive fluid so that currentcan pass from the coiled electrode 62 and through the fluid so that thefluid can be used to ablate tissue. The proximal and distal ends of theporous sleeve 64 can be attached to the distal shaft 16 by any suitablemethod that provides a fluid-tight seal to prevent fluid from leakingout the ends of the porous sleeve. In one embodiment, a plastic thread(not shown), such as a Dacron® thread, is wrapped and cinched around theends of the porous sleeve 64 and then sealed with polyurethane glue orthe like. Such a porous electrode arrangement is described in moredetail in U.S. patent application Ser. No. 09/073,907, entitled“Irrigated Ablation Device Assembly,” the entire disclosure of which isincorporated herein by reference.

[0044] To introduce saline or other fluid to the irrigation openings 66,an infusion tube 68 is provided within the catheter shaft 12. Theinfusion fluid 68 has a distal end mounted in the proximal end of thethird lumen 34 a in the distal region 22 of the catheter shaft 12, and aproximal end that extends outside the catheter through the controlhandle 18, but could alternatively extend out through a sidearm, as isgenerally known in the art. A luer hub 69 is mounted on the proximal endof the infusion tube 68 so that fluid can be introduced into theinfusion tube, through the third lumen 34 a in the distal region 22 ofthe catheter shaft 12, through the third lumen 34 b of the intermediateshaft 14, through the third lumen 34 c of the distal shaft 16 and outthrough the irrigation openings 66. In the depicted embodiment, thedistal end of the distal shaft 16 is sealed with polyurethane glue orthe like to prevent fluid from passing out through the distal end of thethird lumen 34 c, although other mechanisms for closing the distal endof the distal shaft can also be used.

[0045] Additionally, an electrode lead wire 70 is provided toelectrically connect the coil electrode 62 to a source of radiofrequency (RF) energy or other type of ablation energy. The electrodelead wire 70 extends through the central lumen 24 of the proximal region20 of the catheter shaft 12, through the first lumen 30 a of the distalregion 22 of the catheter shaft, through the first lumen 30 b of theintermediate shaft 14, through the first lumen 30 c of the distal shaft16, and out through a lead wire opening (not shown) in the distal shaft.Within the central lumen 24 of the catheter shaft 12, the lead wire 70extends through a protective tube 71 to prevent the lead wire frominterfering with other components in the central lumen, although theprotective tube can be eliminated if desired. Preferably the lead wireopening is potted with polyurethane glue or the like to prevent fluidfrom passing into the first lumen 30 c through the lead wire opening.The distal end of the lead wire 70 is then soldered, welded or otherwiseelectrically connected to the underside of the coil electrode 62. Theproximal end of the lead wire 70 extends through the control handle 18and is connected to a suitable connector (not shown), which can be partof the control handle, that is connected to a source of ablation energy,as is generally known in the art.

[0046] In the depicted embodiment, the distal shaft 16 also carries fourring electrodes 72, although the presence and number of the ringelectrodes can vary as desired. The ring electrodes 72 are particularlyuseful for mapping electrical activity within the heart and can beelectrically connected to an appropriate monitoring apparatus (notshown) as is generally known in the art. Two ring electrodes 72 aremounted distal to the coil electrode 62, and the other two are mountedproximal to the coil electrode, all within the porous sheath 64.Alternatively, the ring electrodes 72 can be mounted over the proximaland distal ends of porous sheath 64 so long as they do not extend overthe region over which the coil electrode 62 extends. Lead wires 70electrically connect the ring electrodes 72 to a monitoring apparatus ina manner similar to the connection of a lead wire to the coil electrodeor in any other manner known to those skilled in the art.

[0047] One or more thermocouples 74 can also be provided for monitoringthe temperature of the tissue being ablated. In the depicted embodiment,two thermocouples 74 are provided, one just proximal to the coiledelectrode 62 and one just distal to the coiled electrode. In addition orin the alternative, thermocouples could be provided in other locations,such as between the coils of the coiled electrode, or eliminatedaltogether. Each thermocouple comprises a pair of thermocouple wires 74that extend, along with the lead wires 70, through the central lumen 24of the proximal region 20 of the catheter shaft 12, through the firstlumen 30 a of the distal region 22 of the catheter shaft, through thefirst lumen 30 b of the intermediate shaft 14, through the first lumen30 c of the distal shaft 16 and out through a thermocouple opening (notshown) in the distal shaft. The thermocouple openings are preferablypotted with polyurethane glue or the like to hold the thermocouples 74in place and to prevent fluid from passing into the first lumen 30 c ofthe distal shaft 16.

[0048] As would be recognized by one skilled in the art, the distalshaft 16 can carry a variety of other electrode configurations. Otherparticularly useful electrode configurations for use with the inventivehinge design are described in U.S. Pat. No. 6,371,955, U.S. patentapplication Ser. No. 09/551,467, entitled “Catheter Having MappingAssembly,” U.S. patent application Ser. No. 10/107,899, entitled“Bidirectional Catheter Having Mapping Assembly,” and U.S. patentapplication Ser. No. 10/118,680, entitled “Catheter Having CircularAblation Assembly,” the entire disclosures of which are incorporatedherein by reference. The distal shaft 16 could also carry othermeasurement and/or treatment devices, such as optic fibers, needles orballoons. The particular measurement or treatment device carried by thecatheter is not critical to the invention.

[0049] The catheter can also include a mechanism for deflecting thedistal region 22 of the catheter shaft 12. In the depicted embodiment, apuller wire 76 extends through proximal region 20 of the catheter shaft12, is anchored at its proximal end to the control handle 18, and isanchored at its distal end to the distal region 22 of the cathetershaft. The puller wire 76 is made of any suitable metal, such asstainless steel or Nitinol, and is preferably coated with Teflon® or thelike. The coating reduces the surface friction on the puller wire 76during deflection.

[0050] A compression coil 78 is situated within the proximal region 20of the catheter shaft 12 in surrounding relation to the puller wire 76.The compression coil 78 extends from the proximal end of the cathetershaft 12 to the proximal end of the distal region 22 of the cathetershaft. The compression coil 78 is made of any suitable metal, preferablystainless steel. The compression coil 78 is tightly wound on itself toprovide flexibility, i.e., bending, but to resist compression. The innerdiameter of the compression coil 78 is preferably slightly larger thanthe diameter of the puller wire 76. The Teflon® coating on the pullerwire 76 allows it to slide freely within the compression coil 78. Ifdesired, the outer surface of the compression coil 78 is covered by aflexible, non-conductive sheath 80, e.g., made of polyimide tubing, toprevent contact between the compression coil and the lead wires and/orthermocouple wires within the catheter shaft 12.

[0051] The compression coil 78 is anchored at its proximal end to theouter wall 26 of the catheter shaft 12 by proximal glue joint 82 and atits distal end to the distal region 22 by distal glue joint 84. Bothglue joints 82 and 84 preferably comprise polyurethane glue or the like.The glue may be applied by means of a syringe or the like through a holemade between the outer surface of the catheter shaft 12 and the centrallumen 24.

[0052] The puller wire 76 extends into the second lumen 32 a of thedistal region 22 of the catheter shaft 12. Preferably the puller wire 76is anchored at its distal end to the side of the distal region 22, asshown in FIGS. 11 to 13. A T-shaped anchor 86 is formed which comprisesa short piece of tubular stainless steel 88, e.g., hypodermic stock,which is fitted over the distal end of the puller wire 76 and crimped tofixedly secure it to the puller wire. The distal end of the tubularstainless steel 88 is fixedly attached, e.g., by welding, to a stainlesssteel cross-piece 90, such as stainless steel ribbon or the like. Thecross-piece 90 sits in a notch 92 in a wall of the distal region 22 thatextends into the second lumen 32 a. The stainless steel cross-piece 90is larger than the notch 92 and, therefore, cannot be pulled through thenotch. The portion of the notch 92 not filled by the cross-piece 90 isfilled with glue or the like, preferably a polyurethane glue, which isharder than the material of the distal region 22. Rough edges, if any,of the cross-piece 90 are polished to provide a smooth, continuoussurface with the outer surface of the distal region 22. Within thesecond lumen 32 a of the distal region 22, the puller wire 76 extendsthrough a plastic, preferably Teflon®, puller wire sheath 94, whichprevents the puller wire 76 from cutting into the wall of the distalregion 22 when the distal region is deflected. Any other suitabletechnique for anchoring the puller wire 76 in the distal region 22 canalso be used. Alternatively, other means for deflecting the distalregion can be provided, such as the deflection mechanism described inU.S. Pat. No. 5,537,686, the disclosure of which is incorporated hereinby reference.

[0053] Longitudinal movement of the puller wire 76 relative to theproximal region 20 of the catheter shaft 12, which results in deflectionof the distal region 22, is accomplished by suitable manipulation of thecontrol handle 18. Examples of suitable control handles for use in thepresent invention are disclosed, for example, in U.S. Pat. Nos. Re34,502 and 5,897,529, the entire disclosures of which are incorporatedherein by reference. However, the precise structure of the controlhandle is not critical so long as it is capable of manipulating thepuller wire or other means for deflecting the distal region.

[0054] If desired, two or more puller wires can be provided to enhancethe ability to manipulate the tip section. In such an embodiment, asecond puller wire and a surrounding second compression coil extendthrough the catheter body and into an additional off-axis lumen in thetip section. The first puller wire is preferably anchored proximal tothe anchor location of the second puller wire. Suitable designs ofcatheters having two or more puller wires, including suitable controlhandles for such embodiments, are described, for example, in U.S. Pat.Nos. 6,171,277, 6,123,699, 6,183,463, and 6,198,974, the disclosures ofwhich are incorporated herein by reference.

[0055] Because in the depicted embodiment the puller wire 76 terminatesin the catheter shaft 12, the second lumens 32 b and 32 c of theintermediate shaft 14 and the distal shaft 16 are empty. However, ifdesired, the puller wire 76 could instead be anchored in the distalshaft 16 in manner essentially identical to that described above withrespect to the distal region 22 of the catheter shaft 12 so as to permitthe use to actively deflect the distal shaft. Alternatively, separatepuller wires (not shown) could be provided for deflection of the distalregion 22 of the catheter shaft 12 and for deflection of the distalshaft 16.

[0056] In use, a suitable guiding sheath is inserted into the patient.An example of a suitable guiding sheath for use in connection with thepresent invention is the Preface™ Braided Guiding Sheath, commerciallyavailable from Biosense Webster (Diamond Bar, Calif.). The distal end ofthe sheath is guided into one of the atria or other region of the heart.A catheter according to the present invention is fed through the guidingsheath until its distal end extends out of the distal end of the guidingsheath.

[0057] Once inside the heart, the distal shaft is positioned for thedesired mapping or treatment procedure. If the distal shaft carries aporous electrode, the porous electrode can then be used to formcontinuous linear lesions by ablation. If the distal shaft carries otherelectrode arrangements, the electrodes can be used for ablating ormapping, as desired. If the distal shaft carries some other component,such as a balloon or optic fiber, that other component can be used fordiagnosis and/or treatment as is generally known in the art. Thepositioning of the distal shaft can be performed by simply pushing thedistal shaft against the heart tissue to thereby cause the distal shaftto deflect or bend toward the catheter shaft. The presence of the hingewill enhance the ability of the distal shaft to bend in a single planein the desired direction and can also limit the extent to which thedistal shaft bends. Alternatively, if a puller wire or other deflectionmechanism is provided within the distal shaft, the user can activelydeflect or bend the distal shaft, with the hinge again serving toenhance the the ability of the distal shaft to bend in a single plane inthe desired direction and optionally limit the extent to which thedistal shaft bends.

[0058] The preceding description has been presented with reference topresently preferred embodiments of the invention. Workers skilled in theart and technology to which this invention pertains will appreciate thatalterations and changes in the described structure may be practicedwithout meaningfully departing from the principal, spirit and scope ofthis invention.

[0059] Accordingly, the foregoing description should not be read aspertaining only to the precise structures described and illustrated inthe accompanying drawings, but rather should be read consistent with andas support to the following claims which are to have their fullest andfair scope.

1. A method for treating tissue comprising: introducing into a patientthe distal end of a catheter comprising: a catheter shaft comprising anelongated tubing having proximal and distal ends, a distal shaftcomprising a tubing having proximal and distal ends, wherein the distalshaft carries a treatment device having a surface along a side of thedistal shaft, and a hinge mounted between the distal end of the cathetershaft and the proximal end of the distal shaft, wherein the hingeenhances the ability of the distal shaft to bend relative to thecatheter shaft in a single predetermined plane; exerting a force on thedistal shaft to cause at least a portion of the surface of the treatmentdevice that is along a side of the distal shaft to contact the tissue;and treating the tissue with the treatment device.
 2. The methodaccording to claim 1, wherein the tissue is heart tissue.
 3. The methodaccording to claim 1, wherein the surface of the treatment device ispositioned on a side of the distal shaft that lies in the predeterminedplane.
 4. The method according to claim 1, wherein the treatment devicecomprises an electrode.
 5. The method according to claim 1, wherein thetreatment device comprises a ring electrode mounted in surround relationto the distal shaft.
 6. The method according to claim 1, wherein thetreatment device comprises a tip electrode.
 7. The method according toclaim 1, wherein the distal shaft comprises an elongated tubularelectrode.
 8. The method according to claim 1, wherein the hingeprohibits the distal shaft from bending relative to the catheter shaftmore than approximately 90°.
 9. The method according to claim 1, furthercomprising a control handle mounted at the proximal end of the cathetershaft and means for deflecting the distal shaft relative to the cathetershaft by manipulation of the control handle.
 10. The catheter accordingto claim 9, wherein the deflecting means comprises a puller wire havinga proximal end anchored in the control handle and a distal end anchoredin the distal shaft.
 11. A method for treating heart tissue comprising:introducing into the heart of a patient the distal end of a cathetercomprising: a catheter shaft comprising an elongated tubing havingproximal and distal ends, a distal shaft comprising a tubing havingproximal and distal ends, wherein the distal shaft carries an electrodehaving a surface along a side of the distal shaft, and a hinge mountedbetween the distal end of the catheter shaft and the proximal end of thedistal shaft, wherein the hinge enhances the ability of the distal shaftto bend relative to the catheter shaft in a single plane; exerting aforce on the distal shaft to cause at least a portion of the electrodesurface that is along a side of the distal shaft to contact the hearttissue; and ablating the heart tissue with the electrode.
 12. The methodaccording to claim 11, wherein the electrode is a ring electrode. 13.The method according to claim 11, wherein the electrode is a tipelectrode.
 14. The method according to claim 11, wherein the electrodeis an elongated tubular electrode.
 15. The method according to claim 11,wherein the surface of the electrode is positioned on a side of thedistal shaft that lies in the predetermined plane.
 16. The methodaccording to claim 1, wherein the hinge prohibits the distal shaft frombending relative to the catheter shaft more than approximately 90°. 17.The method according to claim 11, further comprising a control handlemounted at the proximal end of the catheter shaft and means fordeflecting the distal shaft relative to the catheter shaft bymanipulation of the control handle.
 18. The catheter according to claim17, wherein the deflecting means comprises a puller wire having aproximal end anchored in the control handle and a distal end anchored inthe distal shaft.